The Supreme Court on Tuesday pulled up the Central Bureau of Investigation for "acting at the behest" of the Centre in the disproportionate assets case against Samajwadi Party chief Mulayam Singh Yadav [Images].

"You (CBI) are acting at the behest of central government and the Law Ministry. You are not acting on your own," a bench comprising Justice Altmas Kabir and Justice Cyriac Joseph said.

The court's observations came when Additional Solicitor General Mohan Parasaran said that the opinion of the Law Ministry was sought to withdraw an application filed by the CBI in which it had sought to file a report on inquiry before the apex court and not to the Centre.

"You realise what you are saying. It is very unusual. It is because central government gave the opinion that you filed the interim application (for withdrawal of the earlier application seeking to file the report on inquiry to the apex court)," the bench said.

"Why did you file the interim application on the opinion of the central government? It is incomprehensible," the bench said.

The apex court had ordered a CBI enquiry on the alleged accumulation of disproportionate assets by Yadav, his sons -- Akhilesh, Prateek -- and daughter-in-law Dimple on a public interest litigation (PIL) by an advocate Vishwanath Chaturvedi.

"Why did you go to the central government? You should have come to us," the bench said.

The court wanted to know from the ASG what the other ground to support the application for withdrawal of its earlier plea was.

The ASG said there were other legal grounds which were more in the nature of technical submissions. He said the CBI will abide by the decision of the court.

Solicitor General G E Vahanvati, appearing for the Centre, contended that the concern of the Law Ministry was that the facts should be properly verified as representations have been received from the Yadav family.

The CBI's flip-flop in the case against has drawn the ire of the apex court.

Amid allegations of Centre trying to bail out the former UP CM, the investigating agency replaced Additional Solicitor General Gopal Subramanium with Parasaran to represent it.

The decision to replace Subramanium with Parasaran had also surprised the bench, which made it clear that it will not allow any last minute changes in counsel.

The CBI had on December 6, 2007, moved the apex court seeking withdrawal of its earlier application of October 2007, in which it had sought permission to place a status report before the court instead of submitting it to the central government as per the March 1, 2007, order.

However, the investigating agency during the hearing on January 6 was criticised by the Bench which had said it would not like the agency to become an instrument of the government.

The apex court had earlier rejected the plea of Yadav and his family that the PIL was motivated and filed by Chaturvedi as he was allegedly a Congress activist.

"The ultimate test in our view, therefore, is whether the allegations have any substance. An enquiry should not be shut out at the threshold because a political opponent of a person, with political differences, raises an allegation of commission of offence," the apex court had observed while ordering the CBI enquiry.

Subsequently, the Yadavs filed a review petition but the same could not be adjudicated after Justice A R Lakshmanan (since retired) withdrew himself from hearing, following an anonymous letter, which according to the judge, virtually questioned his integrity.